/*
   A C-program for MT19937, with initialization improved 2002/1/26.
   Coded by Takuji Nishimura and Makoto Matsumoto.

   Before using, initialize the state by using init_genrand(seed)
   or init_by_array(init_key, key_length).

   Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

     3. The names of its contributors may not be used to endorse or promote
        products derived from this software without specific prior written
        permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


   Any feedback is very welcome.
   http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
   email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
*/

///////////////////////////////////////////////////////////////////////////////
//
//    Copyright 2010-2012 Geoffrey TOURON (geoffrey.touron@gmail.com)
//
//    This file is part of Chasis.
//
//    Chasis is free software: you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    (at your option) any later version.
//
//    Chasis is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU General Public License for more details.
//
//    You should have received a copy of the GNU General Public License
//    along with Chasis.  If not, see <http://www.gnu.org/licenses/>.
//
///////////////////////////////////////////////////////////////////////////////

#include <ctime>
#include "mt19937.hpp"

int const Mt19937::N = 624;
int const Mt19937::M = 397;
unsigned long int const Mt19937::MATRIX_A = 0x9908b0dfUL;
unsigned long int const Mt19937::UPPER_MASK = 0x80000000UL;
unsigned long int const Mt19937::LOWER_MASK = 0x7fffffffUL;

Mt19937				&Mt19937::get_instance()
{
	static Mt19937	instance((unsigned long)time(0));

	return (instance);
}

Mt19937::Mt19937(unsigned long s)
{
    (*this)(s);
}

Mt19937::Mt19937(int key_length, unsigned long *init_key)
{
	(*this)(key_length, init_key);
}

Mt19937::~Mt19937()
{

}

Mt19937	&Mt19937::operator()(unsigned long s)
{
    mt[0]= s & 0xffffffffUL;
    for (mti = 1; mti < N; mti++)
    {
        mt[mti] = (1812433253UL * (mt[mti - 1] ^ (mt[mti - 1] >> 30)) + mti);
        /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
        /* In the previous versions, MSBs of the seed affect   */
        /* only MSBs of the array mt[].                        */
        /* 2002/01/09 modified by Makoto Matsumoto             */
        mt[mti] &= 0xffffffffUL;
        /* for >32 bit machines */
    }
	return (*this);
}

/* initialize by an array with array-length */
/* init_key is the array for initializing keys */
/* key_length is its length */
/* slight change for C++, 2004/2/26 */
Mt19937	&Mt19937::operator()(int key_length, unsigned long *init_key)
{
    int	i;
    int	j;

    (*this)(19650218UL);
    i = 1;
    j = 0;
    for (int k = (N > key_length ? N : key_length); k; k--)
    {
        mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1664525UL)) + init_key[j] + j; /* non linear */
        mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
        i++;
        j++;
        if (i >= N)
        {
        	mt[0] = mt[N - 1];
        	i = 1;
		}
        if (j >= key_length)
			j = 0;
    }
    for (int k = N - 1; k; k--)
    {
        mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL)) - i; /* non linear */
        mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
        i++;
        if (i >= N)
        {
        	mt[0] = mt[N - 1];
			i = 1;
		}
    }
    mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
	return (*this);
}

/* generates a random number on [0,0xffffffff]-interval */
unsigned long				Mt19937::genrand_int32()
{
    unsigned long			y;
    static unsigned long	mag01[2] = { 0x0UL, MATRIX_A };
    /* mag01[x] = x * MATRIX_A  for x = 0, 1 */

    if (mti >= N)
    { /* generate N words at one time */
        int kk;

        for (kk = 0; kk < N - M; kk++)
        {
            y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
            mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL];
        }
        for (; kk < N - 1; kk++)
        {
            y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
            mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
        }
        y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
        mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL];
        mti = 0;
    }
    y = mt[mti++];
    /* Tempering */
    y ^= (y >> 11);
    y ^= (y << 7) & 0x9d2c5680UL;
    y ^= (y << 15) & 0xefc60000UL;
    y ^= (y >> 18);
    return (y);
}

/* generates a random number on [0,0x7fffffff]-interval */
long	Mt19937::genrand_int31()
{
    return ((long)(genrand_int32() >> 1));
}

/* generates a random number on [0,1]-real-interval */
double	Mt19937::genrand_real1()
{
    return (genrand_int32() * (1.0 / 4294967295.0));
    /* divided by 2^32-1 */
}

double	Mt19937::genrand_real1(double min, double max)
{
	return (min + genrand_int32() * (1.0 / 4294967295.0) * (max - min));
}
/* generates a random number on [0,1)-real-interval */
double	Mt19937::genrand_real2()
{
    return (genrand_int32() * (1.0 / 4294967296.0));
    /* divided by 2^32 */
}

/* generates a random number on (0,1)-real-interval */
double	Mt19937::genrand_real3()
{
    return ((((double)genrand_int32()) + 0.5) * (1.0 / 4294967296.0));
    /* divided by 2^32 */
}

/* generates a random number on [0,1) with 53-bit resolution*/
double				Mt19937::genrand_res53()
{
    unsigned long	a = genrand_int32() >> 5, b = genrand_int32() >> 6;
    return ((a * 67108864.0 + b) * (1.0 / 9007199254740992.0));
}
/* These real versions are due to Isaku Wada, 2002/01/09 added */
